1. Field of the Invention
The present invention relates to a tube fitting and more particularly to the tube fitting having a main body so formed as to be tubular-shaped and so configured as to lock a tube inserted from an opening part on one end side of the main body and to be able to hold the tube.
2. Description of the Related Art
One example of a conventional tube fitting is disclosed in Patent reference 1 (Japanese Patent Application Laid-open No. 2002-106772). The conventional tube fitting disclosed in the Patent reference 1 has a pipe-shaped main body of a fitting, a guiding tubular body one end of which is inserted into the fitting main body with pressure and is fixed in the fitting main body, a stopper fixed in the guiding tubular body in a state where one end of a guiding case is caulked, an open tubular body held by one end of the guiding tubular body so as to be freely moved in an axial direction, a seal ring, and a locking nail. The tube fitting having the above components is configured to be connected to a connection hole of an external fluid apparatus (see Patent reference 1, FIG. 1, Paragraph no. 0008).
According to the conventional tube fitting, a tube to be connected to an external fluid apparatus is inserted through an inserting entrance of the main body of the fitting (the open case and guiding case make up the inserting entrance). At this point of time, a locking nail is widened outward by an end of the tube and the end of the tube come into contact with an outer circumferential surface of the tube in a state of being struck. In this state, when the tube is pulled and moved toward a pulling and removing direction, the end of the locking nail bites an outer wall of the tube, thereby inhibiting the pulling and removing of the tube. Moreover, in order to pull and remove the tube, the open tubular body is put therein under pressure to release the biting (see Patent reference 1, paragraph 0009).
When a tube is connected to an external fluid apparatus handling a fluid, ordinarily, a plurality of tube fittings to be connected to a connection port of the external fluid apparatus through which the fluid flows in and out, and is placed in a state of being in proximity to one another or being gathered in an intimate manner or positioned in a hard-to-reach place or in a hard-to-see place for an operator of the external fluid apparatus in many cases.
However, the conventional tube fitting as shown in the Patent reference 1 has a problem in that, when a tube is pulled out from the main body of the fitting, it is necessary that the open tubular body is put therein with pressure and the tube is pulled out in a pulling and removing direction and, therefore, manipulation of the fitting and tube with both hands is required, which makes it difficult to perform easy attaching and detaching operations. In particular, as described above, a problem arises in the case where the tube fittings are placed in a state of being in proximity to one another or being gathered in an intimate manner or positioned in a hard-to-reach place or in a hard-to-see place for an operator of the external fluid apparatus, the operation of putting the open tubular body therein with pressure is not easy.
To solve these problems, another tube fitting is disclosed in Patent reference 2 (Japanese Patent Application Laid-open No. 2005-172218) in which a tube can be easily attached and detached only by manipulating the tube with one hand (see FIG. 8). The conventional tube fitting 100 is so configured as to be tubular-shaped and is made up of a fitting main body 102 into which a tube P is inserted from an opening part 106 on one end and a locking member 104 mounted in the fitting main body 102 and locks the tube P inserted into the fitting main body 102 on the fitting main body 102 and holds the tube P, and the locking member 104 includes a ring part 110 whose outer circumferential part is in contact with an inner wall of the filling main body 102 and is configured to be movable toward an axial direction of the fitting main body 102 and an extended part 114 having flexibility which extends from the ring part 110 toward the opening part 106 of the fitting main body 102 and at an end of which a nail part 112 proceeding inward in the fitting main body 102 is formed. The fitting main body 102 has a tapered part 122 whose diameter is gradually decreased on the opening part side 106 and, when the locking member 104 moves toward the opening part 106 side, an end part of the extended part enters to decrease the diameter of the end part and locks a tube P by the nail part 112.